1. Field of the Invention
This invention relates to structure of surface-discharge-type alternating-current plasma display panels.
The present application claims priority from Japanese Application No. 2007-166599, the disclosure of which is incorporated herein by reference.
2. Description of the Related Art
FIG. 1 is a front view illustrating the structure of a conventional surface-discharge-type alternating-current plasma display panel. A surface-discharge-type alternating-current plasma display panel is hereinafter abbreviated as “PDP”.
In FIG. 1, the conventional PDP comprises a plurality of row electrode pairs (X, Y) provided on the front glass substrate and a plurality of column electrodes D(R), D(G), D(B) provided on the back glass substrate which face the front glass substrate across the discharge space S. The column electrodes D(R), D(G), D(B) respectively intersect with the row electrode pairs (X, Y) such that discharge cells C are formed in the discharge space S corresponding to the respective intersections. Each of the face-to-face row electrodes X and Y constituting each of the row electrode pairs (X, Y) is made up of T-shaped transparent electrodes Xa (Ya) formed of a transparent conductive film such as an ITO film and a metal-film-formed bus electrode Xb (Yb) which extends in the row direction and is connected to the base ends of the transparent electrodes Xa (Ya).
Each of the column electrodes D(R), D(G), D(B) faces the transparent electrodes Xa and Ya which face and are paired with each other across a discharge gap g.
The column electrodes D(R), D(G) and D(B) respectively have widened portions D(R)a, D(G)a and D(B)a each formed in a portion corresponding to the head end of the transparent electrode Ya. The widened portions D(R)a, D(G)a, D(B)a have a row-direction width greater than those of the respective other portions of the column electrodes D(R), D(G), D(B). Each of the column electrodes D(G) faces the discharge cells C in which green phosphor layers are respectively provided. The row-direction width of the widened portion D(G)a of the column electrode D(G) is set greater than those of the widened portions D(R)a and D(B)a of the column electrodes D(R) and D(B) which respectively face the discharge cells C with red and blue phosphor layers respectively provided therein.
A PDP having such a conventional structure is disclosed in Japanese Unexamined Patent Publication No. 2003-16944.
This conventional PDP has the advantage of offering stable discharge characteristics. This is because, when an address discharge which is an opposing discharge is initiated through the phosphor layers interposed between the head end of the transparent electrode Ya of the row electrodes Y and the corresponding column electrode D(R), D(G) or D(B) in each discharge cell, the widened portion D(R)a, D(G)a or D(B)a of the column electrode D(R), D(G) or D(B) causes the address discharge to occur with a concentration on the head end of the transparent electrodes Ya facing the widened portion.
In the conventional PDP, a discharge does not easily occur through the green phosphor layer, so that the column electrode D(G) disposed facing the discharge cells C in which the green phosphor layers are provided has widened portions D(G)a each having a greater row-direction width than that of each of the widened portions of the other column electrodes D(R), D(B). This difference in size of the widened portions prevents the discharge characteristics from being varied by the difference among the phosphor materials forming the respective phosphor layers provided in the discharge cells C. In consequence, the conventional PDP additionally has the ability of uniformly producing the address discharge in the discharge cells, thus expanding the voltage margin.
However, the row-direction width of each discharge cell C is increasingly reduced along with the higher definition image because of the development of PDPs such as a full HD PDP in recent years. Accordingly, as in the conventional PDP, when a widened portion is provided in the column electrode and the widened portion of a column electrode facing a discharge cell in which a phosphor layer of a required color is formed has a greater row-direction width than that of another widened portion of another column electrode facing a discharge cell in which a phosphor layer of a different color is formed, the opposing ends of the greater widened portion of the column electrode may possibly overlie a part of a partition wall unit P partitioning the discharge space into the discharge cells as shown in FIG. 1.
The conventional structure of the PDP as described above may possibly have the disadvantages of causing an increase in the electrostatic capacity caused between the row electrode and the column electrode by the partial overlie between the column electrode and the partition wall unit, and of a rise in the discharge voltage during the address discharge, and the like.